To avoid possible heat damage to your oven, we do not recommend using aluminum foil to line the bottom of your oven. Rather, we recommend that you place a sheet of heavy duty aluminum foil on the oven rack beneath the pie or casserole you are baking. The foil should be only a few inches larger than the baking pan to allow for proper heat circulation. The foil will catch any drips before they reach the oven bottom.

There you go. Smart play on Reynolds part, right? Because you know people will end up getting rid of the sheet of foil and using a new one next time…